Yeah Ok so I admit it - I used to own a Punto ....
and it had spacesaver spare. On the 1 occasion that I had to use it ( on the front axle ) there was a definite noise from the gearbox as the differential was ' wound up ' by the difference in size between the spacesaver & the standard road wheel.
Probably since the difference is even greater for MINI with 16" rims this is even more of a problem and could cause gerabox damage ?